Improved step-ladder



UNITED PATENT OFFICE.

VVILLYIAMi EUGENEYBOD, OF CLEVELAND, OHIO.

IM PPtOVE'II) STEP- LADDER.

Specilication forming part ot" Letters Patent N01 42;, I 62dated April 5, 1864.

To all whom it may concern Be it known that I, WILLIAM EUGENE BOND, of Cleveland, in the county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Step-Ladders; and I do hereby declare that the iollowing is afull and complete description of the construction and operation of the same, reference being had to the accompanying drawings, making part of this specification, in which- Figure lis a front view, and Fig. 2 is a side view.

Like letters refer to like parts in the several views. v

The nature of my invention relates to such a construction of the side bars and step-boards as to give strength to sustain a weight, and to guard against a lateral swaying', while at the same time lightness of structure is secured. The side bars A A consist of two pieces each, (shown at a a,) secured together at the ends by screws or bolts, and separated in the middle about five or six inches; or they may be made of one piece of board each by removing the middle portion to within a foot, or thereabout, of the ends, in which case it would be proper to pass a screw or bolt through, near each end, to prevent them from s plittin g. In either form of construct-ion each section a a. should be about two inches wide, or even less, and about an inch in thickness, and the space between the sections a c', in the middle, from tive to six inches, as above stated, according to the size of the ladder. The ends of the lower step, B, are vcut at nearly right angles, as shown at b b in detached view in Fig. 3, and is let into the inner faces of the bars A at a suitable distancefrom thelower end forthe rst step, and secured by screws to each section a a', or otherwise. The step-board B will therefore occupy the position in relation to the sides A as shown in cross-section at A A', the point of which cross-section is shown by the red lines x in Figs. l and 2, the crossseetion being shown in Fig. 3. The step Gis about two inches shorter on the front edge than the step B, and has its ends cut at a sharper angle than the step B, (measuring from the front edge,) as seen at o c in Fig. 3. The side bars a a are consequently twisted inward upon their inner edges, in order to cause them to conform to the ends of the stepboard C-that is, the sections a a of the side bars A are brought nearer together, relatively, than the sections a a, which gives the side bars A, as a whole, aspiral or winding form from the lower end to the middle in reversed order, so that ,the red lines y y in Figs. l and l would showin cross-section the position represented at D D in Fig. 3. The stepboard E has its ends cut at the same angle as that of C, but is about two inches shorter, and, being secured firmly to both the side bars at a proper distancefor the step, preserves this twisted and spiral form of the side bars to this point; but by reason of each succeeding step-board being shorter than that below it the side bars are caused to approach each other toward the top. The step F has its ends cut at the angle of the step B, and being secured firmly to the side Apieces A A, as

` is the other step-boards, reverses the spirality of the sides A A by turning the inner edges again outward, which brings the two sidehbars A A back to the position shown in cross-section at G, Fig. 3, the same point being represented by the red lines z z in Figs. l and 2. Thus, by cutting the ends of the step-boards at constantly-varying angles and compressing the side bars A A to correspond therewith and securing them iirmly together, the two side bars are caused to have a twisted or spiral form from the bottom to the middle in opposite directions and in reverse order from the middle to the top. The effect of this double spirality is equivalent to an increased thickness in the middle of the bars A A, equal to the difference in the distance between the dotted lines H H and I I in Fig. 3, thus giving great resistance against a lateral pressure, without any increase of weight in the material used in the structure. Any number of step-boards may be used, in order to give the ladder any desired height, and in the variation of the number of step-boards the angle of the ends must be varied accordingly, and thevariation in the length of the front edge of the step-boards will give the desired inclination of the upper ends of the side pieces or bars Vtoward each other, thus making the whole structure narrower at the top than at Vthe bottom. The two bars A A are secured together at the top by a board, J, lwhich is screwed or nailed to the back edge of both, as

shown in the figures, and the upper step or platform, K, is secured to this and to the upper end of the side pieces A, and is about twice the Width of the stepboards below. rlhe platform K is in length about equal to the step-hoard E. The back brace consists of two rods, L, which are hinged to the lower edge of the board J as shown at M. Thelower ends of these rods are held in place by diagonal braces N and a stay-piece, O, near the middle. The back brace can be placed at any desired an gie when the ladder is in use. Its proper position is shown in Fig. 2. It can be folded against th bars a" a! when not in use.

specified.

WILLIAM EUGENE BOND. Witnesses J. BRMNERD, W. Il. BURRIDGE. 

